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Joint China and Japan ChaoJi project works towards “CHAdeMO 3.0”

Good progress is being reported on the joint effort by the predominantly Japanese CHAdeMO Association and China’s State Grid utility operator on their new common connector plug design for future vehicles from both countries.

Last summer they announced an agreement to work together on a common connector design called ChaoJi for future use in Japan, China, and other regions of the world using the CHAdeMO or GB/T connector today. ChaoJi (超级) means “super” in Chinese.

CHAdeMO is the DC fast charging connector design used, for example, in the Nissan LEAF. Electric vehicles sold in China use a GB/T charging standard unique to China.

Details of the ChaoJi effort were initially sketchy but are now becoming more clear. The goal is to design a new common plug and vehicle inlet that can support up to 600A at up to 1,500V for a total power of 900 kW. This compares to the CHAdeMO 2.0 specification updated last year to support 400A at up to 1,000V or 400 kW. China’s GB/T DC charging standard has supported 250A at up to 750V for 188 kW.

Although the CHAdeMO 2.0 specification allows up to 400A there are no actual liquid-cooled cables and plugs commercially available so charging is, in practice, limited to 200A or about 75 kW today on the 62 kWh Nissan LEAF PLUS.

An initial design and matching prototype equipment has been built and is undergoing testing. The goal is to complete the development and submit it to an international standards working group within the next two years.

This photo of a prototype ChaoJi vehicle inlet is taken from the Japanese Car Watch website which covered a CHAdeMO meeting on May 27. See that article for additional images.

By comparison, the CCS specification supported by South Korean, North American, and European car makers supports up to 400A continuously at 1,000V for 400 kW although several companies make CCS chargers that output up to 500A.

A newly updated CCS (known as the SAE Combo 1 or Type 1) standard used in North America has been formally published but the equivalent document describing Europe’s Type 2 variant of the CCS plug design is still in the final stages of review and is not yet publicly available although equipment based on it is already being sold and installed.

The official heading up the European office of the CHAdeMO Association, Tomoko Blech, gave a presentation on the ChaoJi project to attendees at an E-Mobility Engineering Day 2019 meeting organized by the German automotive electronics company Vector at its headquarters in Stuttgart, Germany on April 16.

Correction: an earlier version of this article incorrectly said Tomoko Blech’s presentation was given to a CharIN Association meeting.

The new ChaoJi plug and vehicle inlet design is intended to replace the existing design on future vehicles and their chargers. Future vehicles can use chargers with older CHAdeMO plugs or China’s GB/T plugs by way of an adapter that a driver can temporarily insert into the vehicle inlet.

Older vehicles using CHAdeMO 2.0 and earlier or China’s existing GB/T design, however, are not allowed to use an adapter and can only fast DC charge using the older type of plugs.

The presentation describes a Chinese variant of the newly designed plug called ChaoJi-1 and a Japanese variant called ChaoJi-2 although they are physically interoperable without an adapter. It’s not clear from the presentation what the exact differences are or whether the two variants will be merged before the standard is finalized. The two variants could reflect optional “combo” bundlings of the new common DC ChaoJi plug with the existing AC charging plug standard used in each country analogous to the CCS Type 1 and Type 2 “combo” designs which combined both AC and DC charging together in a single plug.

The existing CHAdeMO and the GB/T standards communicate with the vehicle using CAN bus networking which is also widely used within vehicles to allow components of a car to communicate with each other. The new ChaoJi design continues to use CAN bus which eases backwards compatibility when using inlet adapters with older charger cables.

CCS reuses the same TCP/IP protocols used by computers to access the internet and also uses a subset of another standard called HomePlug to carry the low-level data packets over a low-voltage pin inside the CCS plug. HomePlug can be used for extending computer networks over 120V power lines within a home or business.

This makes it more complex to implement a potential adapter between a CCS charger and a future ChaoJi-based vehicle inlet but engineers working on the project think it should be possible. One could also presumably build an adapter allowing a CCS vehicle to use a ChaoJi charging cable.

Because CCS uses the same communication protocols underlying electronic commerce on the internet it is relatively easy for it to use the TLS security layer used by browsers with websites using “https” links. CCS’s emerging “Plug and Charge” system uses TLS and related X.509 public key certificates to securely allow automatic payment when cars are plugged in for charging without the need for RFID cards, credit cards, or phone apps. Electrify America and European car companies are promoting its deployment later this year.

The CHAdeMO Association has announced that they are working on adapting Plug and Charge for inclusion on the CAN bus networking to be used in ChaoJi.

Like CHAdeMO, ChaoJi will continue to support the bidirectional flow of power so that the battery pack within a car can also be used to export power from the car back into the grid or into a home during a power outage. CCS is working on incorporating this ability.

DC charging adapters are only used today by Tesla. The company sells an adapter for $450 that allows a Tesla vehicle to use a CHAdeMO charging plug. In Europe, Tesla also recently began selling an adapter that allows Model S and Model X cars to use European style CCS (Type 2) charging cables. In a break with the company’s past proprietary connector, the Model 3 is sold in Europe with a native CCS inlet.

Tesla vehicles sold in China use the GB/T standard there today and would presumably switch to the new ChaoJi design at some point in the future.

Tesla recently introduced version 3 of its DC SuperCharger system for the North American market which can now charge its cars using a liquid-cooled cable and plug at higher amperage (apparently near 700A). With the new system, the latest S and X Models can charge at up to 200 kW and the Model 3 can reach a peak near 250 kW.